A woman is not required to marry a man just because he wants to marry her. She is also not required to give a reason for refusing. Marriage is optional.
The opposite is also true - that is, a man is not required to marry a woman just because she wants to marry him, and he is also not required to give a reason for refusing.
The idea a woman must give her life over to a man simply because he asks - unless she had a reasonable excuse - would indeed be an astonishing form of male privilege.